<template>
  <div id="home">
    <nav-bar class="home-nav">
      <div slot="center">购物街</div>
    </nav-bar>
    <tab-control :titles="['流行', '新款', '精选']"
                 @tabClick="tabClick"
                 ref="tabControl1"
                 class="tab-control"
                 v-show="isTabFixed"/>
    <scroll class="content"
            ref="scroll"
            :probe-type="3"
            @scroll="contentScroll"
            :pull-up-load="true"
            @pullingUp="loadMore">
      <home-swiper :banners="banners"
                   @swiperImageLoad="swiperImageLoad"/>
      <recommend-view :recommends="recommends"/>
      <feature-view/>
      <tab-control :titles="['流行', '新款', '精选']"
                   @tabClick="tabClick"
                   ref="tabControl2"/>
      <goods-list :goods="showGoods"/>
    </scroll>

    <back-top @click.native="backClick" v-show="isShowBackTop"/>
  </div>
</template>

<script>
import HomeSwiper from "./childComps/HomeSwiper";
import RecommendView from "./childComps/RecommendView";
import FeatureView from "./childComps/FeatureView";

import NavBar from "components/common/navbar/NavBar";
import TabControl from "components/content/tabControl/TabControl";
import GoodsList from "components/content/goods/GoodsList";
import Scroll from "components/common/scroll/Scroll";

import {getHomeMultidata, getHomeGoods} from "network/home";
import {debounce} from "common/utils";
import {itemListenerMixin, backTopMixin} from "common/mixin";

export default {
  name: "Home",
  components: {
    HomeSwiper,
    RecommendView,
    FeatureView,
    NavBar,
    TabControl,
    GoodsList,
    Scroll
  },
  mixins: [itemListenerMixin, backTopMixin],
  data() {
    return {
      banners: [],
      recommends: [],
      goods: {
        'pop': {page: 0, list: []},
        'new': {page: 0, list: []},
        'sell': {page: 0, list: []}
      },
      currentType: 'pop',
      tabOffsetTop: 0,
      isTabFixed: false,
      saveY: 0,
      // itemImgListener: null
    }
  },
  computed: {
    showGoods() {
      return this.goods[this.currentType].list
    }
  },
  destroyed() {
    console.log('home destroyed');
  },
  activated() {
    this.$refs.scroll.scrollTo(0, this.saveY, 0)
    this.$refs.scroll.refresh()
  },
  deactivated() {
    // 1. 保存Y值
    this.saveY = this.$refs.scroll.getScrollY()

    // 2. 取消全局事件的监听
    this.$bus.$off('itemImageLoad', this.itemImgListener)
  },
  created() {
    // 1. 请求多个数据
    this.getHomeMultidata()

    // 2. 请求商品数据
    this.getHomeGoods('pop')
    this.getHomeGoods('new')
    this.getHomeGoods('sell')
  },
  mounted() {
  },
  methods: {
    /**
     * 事件监听相关的方法
     */
    tabClick(index) {
      switch (index) {
        case 0:
          this.currentType = 'pop'
          break
        case 1:
          this.currentType = 'new'
          break
        case 2:
          this.currentType = 'sell'
          break
      }
      this.$refs.tabControl1.currentIndex = index;
      this.$refs.tabControl2.currentIndex = index;
    },
    contentScroll(position) {
      // 1. 判断BackTop是否显示
      this.isShowBackTop = (-position.y) > 1000

      // 2. 决定tabControl是否吸顶（position: fixed）
      this.isTabFixed = (-position.y) > this.tabOffsetTop
    },
    loadMore() {
      // console.log('加载更多的方法');
      this.getHomeGoods(this.currentType)
    },
    swiperImageLoad() {
      // 获取tabControl的offsetTop
      // 所有的组件都有一个$el：用于获取组件中的元素
      this.tabOffsetTop = this.$refs.tabControl2.$el.offsetTop;
    },
    /**
     * 网络请求相关的方法
     */
    getHomeMultidata() {
      getHomeMultidata().then(res => {
        this.banners = res.data.banner.list;
        this.recommends = res.data.recommend.list;
      })
    },
    getHomeGoods(type) {
      // 获取页码
      const page = this.goods[type].page + 1;
      getHomeGoods(type, page).then(res => {
        this.goods[type].list.push(...res.data.list)
        // 实现页码加1
        this.goods[type].page += 1

        // 完成上拉加载更多
        this.$refs.scroll.finishPullUp()
      })
    }
  }
}
</script>

<style scoped>
  #home {
    /*padding-top: 44px;*/
    height: 100vh;
    position: relative;
  }
  .home-nav {
    background-color: var(--color-tint);
    color: #ffffff;

    /*在使用浏览器原生滚动时，为了让导航不跟随一起滚动*/
    /*position: fixed;*/
    /*left: 0;*/
    /*right: 0;*/
    /*top: 0;*/
    /*z-index: 9;*/
  }

  .content {
    /*height: 300px;*/
    overflow: hidden;

    position: absolute;
    top: 44px;
    bottom: 49px;
    left: 0;
    right: 0;
  }

  .tab-control {
    position: relative;
    z-index: 9;
  }

  /*.content {*/
  /*  height: calc(100% - 93px);*/
  /*  overflow: hidden;*/
  /*  margin-top: 44px;*/
  /*}*/
</style>
